Some wire harnesses installed on vehicles are three-dimensionally arranged in the vehicles. When assembling such a wire harness to be three-dimensionally arranged in a vehicle in this manner, typically, it is two-dimensionally laid out and assembled on an assembly drawing board. Thus, when laying out the two-dimensionally assembled wire harness into a three-dimensional shape, problems occur such as the wire harness being partially twisted.
If the wire harness is twisted, the route of the electric wires constituting the wire harness becomes longer than expected, for example, and thus an operation called tuning to readjust a design value of the electric wire length may be required. A technique for suppressing such twisting is disclosed, for example, in Patent Document 1.
The method for designing a wire harness described in Patent Document 1 is to minimize twisting, by placing a first wire and a second wire or a support member on a main virtual jig face and sub virtual jig faces such that a predetermined binding condition is satisfied.